A large or complex vehicle, such as a commercial aircraft, may include an electric power system that distributes power to various electrical subsystems at different voltage levels and different frequencies. For example, electrically-powered mechanical systems may use alternating current (AC) at relatively high voltage. By contrast, avionics systems conventionally operate on direct current (DC) at relatively low voltage. Other systems may also be present that use power of different characteristics.
On an aircraft, electrical power is typically generated by engine-driven generators. For example, power from an engine aboard the aircraft may be diverted to drive a generator. The electrical power may be converted using transformers, power electronics converters, or combination of both, and other devices to either alternating or direct current at different voltages used by subsystems. Diverting power from the engine increases engine fuel consumption, and the engines may not operate at their highest efficiency. It is desirable to increase efficiency of the aircraft and to decrease the cost of operating the aircraft.